All pixels are not created equal

Resolution requirements for high quality inkjet prints

Native Resolution

The quality of colour and sharpness of your printed images depends on the quality of your pixels. The important ones are the pixels out of your camera or scanner. They are the original pixels also called ‘native’ resolution. These pixels are a function of the Sensor that your camera or scanner is built upon.

The lens, exposure, lighting and software will all determine the quality of your pixels and therefore the detail and resolution of your image. In imaging programs like Photoshop you can add more pixels by interpolation (cloning pixels). These pixels are created by averaging the surrounding pixels. This will increase the amount of pixels in the image but not the details in your image. You will have a larger file but a softer looking image.

We do not recommend that you (clone) interpolate your image unless there is a particular reason for this. As a general rule 100-150 ppi at 100% of print size will deliver a great result but anything from 70 ppi works fine for poster work while the upper range above 100 ppi towards 200 ppi or more is the type of quality images you are looking at creating for fine art prints. Please keep in mind that the viewing distance impacts on how well we can read details in any printed image.

As we print using a Raster Imaging Process (RIP) there is no requirement to scale or optimise your files to a particular size as the scaling up or down will be done by the RIP.
Camera

A standard camera capture is at 3000 x 4000 pixels (32.7Mb) and once cropped to “A sized” proportions it looks approximately like this;

  • A3 2857 x 4000 pixels @ 240 ppi
  • A2 2857 x 4000 pixels @ 170 ppi
  • A1 2857 x 4000 pixels @ 120 ppi
  • A0 2857 x 4000 pixels @ 85 ppi
Master File

The same master file in this example is used for an A3 print but also for A2/A1 and A0 prints without any issues. There is therefore no reason to create multiple versions of a an image for these various sizes. A master file is in proportions to the print ratios you want to print is all you need.

And finally…

Viewing your images at 100% of print size on screen will give you reasonable approximation of how they will print as far as sharpness and resolution. If your image looks pixelated on screen, adding additional pixels through Interpolation will create softer edged pixels without gaining details.

If your artwork contain line work or logos (vector files) in conjunction with images they should ideally combined in InDesign or similar document program and then be supplied as a print ready PDF. That way the vector files will remain at the highest quality while printing.

Check our Image Resolution Guide…

If this document has raised any questions for you please ask us and we will try to clarify.